SQL DB table design for asp.net gaming site

You can use nvarchar datatype to store your dates.
But if you need to search date vaules you can convert your nvarchar to date format.

Hope you might have fixed format startting like Summer,Q1,Mid,TBA and 05-12-2013 depend on the value you can search

Or you can have 3 column in SQL table one as nvarchar and 2 as Date.
before insert data in first column you can insert summer-2015 .You might be know Summer duration of start and end month and date.add the start and end date to other date field.
Same like this you can insert for q1 hope this if first quater might be from Jan 2015 to April 2015 so its you can insert this in 3 columns this method will be easy to do the search funciotn